1. Field of the Invention
The present invention relates to an air conditioning and ventilation system for vehicles.
2. Description of the Prior Art
Recently, an increased number of vehicle are equipped with air conditioning systems to give improved comfort to drivers and passengers. The prior art air conditioning system for vehicles has a room air passage, an outdoor air passage and a damper which is operable by an operator through a mechanical linkage so that the introduction of the fresh outdoor air and the recirculation of the room air are switched over. In the prior art conditioning system, if the change-over damper is placed for a long time in a position to recirculate the room air, the room air becomes polluted by the breathing and smoking of passengers. On the other hand, if the change-over damper is placed for a long time in a position to introduce the outdoor air only into the passenger room, a larger amount of thermal load will be exerted to the air heating and cooling systems, with a resultant disadvantage that the fuel consumption of the engine is increased.